note 46913 added to function.mysql-pconnect

I would like to comment on the post from dfischer at qualcomm dot com that proposes spanning transactions over multiple application invocations, in case someone is bold enough to try it. I'll assume the table types being used are one of those that support transactions, such as InnoDB or BerkeleyDB. First, there is a question of whether this would work at all. To work at all, the transaction context would have to be preserved across all the invocations of the php code through the web server. Reading the description of http://www.php.net/manual/en/features.persistent-connections.php maintaining transaction context would be at best a coincidence. It would be interesting to find out that this does work on occasion and to understand the ramifications of such behavior. If I happened to get your connection and my action was a cancel, your updates might be gone. Second, if such a thing did work (occassionally or always), there would be performance implications as the underlying database managed transactions that were pretty much open-ended. A few long-running transactions would likely eat up many resources in a short time and the likelihood of concurrency conflicts could rise. If the mysql_pconnect behavior is to keep transaction open at the end of php processing, then it would probably be better to not define transactions when using mysql_pconnect. And, transactions that were never closed by code (user went out to lunch and got hit by a bus) could hold resources for quite some time (maybe until after rehab). So, even if such a scheme COULD work, it is not a good idea. The transaction should be committed or rolled back at the end of the user request processing. This allows the DBMS to properly manage resource ultilization and keeps bad things from happening to good data. If mysql_pconnect does not coordinate well with the transaction component of the database engine to always end a transaction at the end of processing a request, then mysql_pconnect should never be used where begin transaction is used. ---- Manual Page -- http://www.php.net/manual/en/function.mysql-pconnect.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+46913 Delete -- http://master.php.net/manage/user-notes.php?action=delete+46913&report=yes Reason: bad code -- http://master.php.net/manage/user-notes.php?action=delete+46913&report=yes&reason=bad+code Reason: spam -- http://master.php.net/manage/user-notes.php?action=delete+46913&report=yes&reason=spam Reason: useless example -- http://master.php.net/manage/user-notes.php?action=delete+46913&report=yes&reason=useless+example Reason: contains commercial links -- http://master.php.net/manage/user-notes.php?action=delete+46913&report=yes&reason=contains+commercial+links Reason: useless note -- http://master.php.net/manage/user-notes.php?action=delete+46913&report=yes&reason=useless+note Reject -- http://master.php.net/manage/user-notes.php?action=reject+46913&report=yes Search -- http://master.php.net/manage/user-notes.php